We consider a cosmological scenario where a relativistic particle and a stable massive particle are simultaneously produced from the decay of a late-decaying particle after Big-Bang Nucleosynthesis but before matter-radiation equality. The relativistic and massive particles behave as dark radiation and warm dark matter, respectively. Due to a common origin, the warmness and abundances are closely related. We refer to the models that lead to such a scenario as Common Origin of Warm and Relativistic Decay Products (COWaRD). We show that COWaRD predicts a correlation between the amount of dark radiation and suppression of the large scale structure, which can be tested in future precision cosmology observations. We demonstrate that COWaRD is realized, as an example, in a class of supersymmetric axion models and that future observations by the next generation Cosmic Microwave Background, Large Scalar Structure, and 21-cm surveys can reveal the structure of the theory.

中文翻译：

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暖暗物质和暗辐射的共同起源

我们考虑一个宇宙学场景，在大爆炸核合成之后但在物质辐射相等之前，一个相对论粒子和一个稳定的大质量粒子同时由晚期衰变粒子的衰变产生。相对论粒子和大质量粒子分别表现为暗辐射和暖暗物质。由于共同的起源，温暖和丰度密切相关。我们将导致这种情况的模型称为暖和相对论衰变产物的共同起源（COWaRD）。我们表明 COWaRD 预测了暗辐射量与大尺度结构抑制之间的相关性，这可以在未来的精密宇宙学观测中进行测试。我们证明了 COWaRD 的实现，作为一个例子，